The password based lock for any access control systems is very common now a day. If there is a password lock for any gate/door, then the gate or door only opens when correct password is entered. Mostly in such system numeric keypad is given to enter password. Sequential code lock differs here with normal password lock system. It does not have full numeric keypad with 10 to 12 switches. Instead it has 2 to 3 switches only.
The performance of each and every electronic system or electronic circuit depends upon the power supply that energizes the circuit or system. It provides required current to the circuit. Any disturbance noise in this power supply can cause problem in working or operation of circuit. If there is any deviation in this power supply level the circuit may not work properly. The accuracy and precision of circuit operation depends upon it. In some of the circuits all the calibration are done at this voltage level. So all these calibrations becomes false if there is fluctuation in supply level. There are two types of power supplies: Unregulated power supply, Regulated power supply. Unregulated supply is used in some circuits where there is no much change in required load current. The load current remains fixed or deviation is very less. Read more to know about this interesting power supply project.
The given project describes how different DTMF tones can be generated using DTMF tone generator chip 91214B and how these tones can be decoded by DTMF decoder chip MT8870 that generates 4-bit digital output.Using these two circuits together one can build DTMF based remote control application in which 91214B chip is used as remote control and MT8870 is used at the receiver side to decode DTMF tones. The 4 bit digital output of MT8870 can be given to micro controller that will control any device or any application as per the button pressed on 91214B based remote control.
There are two methods to increase transmission range of 434 MHz RF Tx module. 1. Increase applied input power – transmitted power2. Attach an antenna to Tx module In previous article I have explained first method. Please refer previous article of this series. In this session we will see another method. That means we will attach an antenna to Tx and Rx module. Antenna is a special type of transducer, which can convert alternating current in to radio frequency fields and vice versa. Transmitting antenna generates RF fields, and receiving antenna converts RF fields in to alternating current.
This Passive InfraRed Alarm system (PIR alarm) can switch on a Lamp or Alarm when it detects the heat from an object like moving person. The name PIR (Passive Infrared) is given to the sensor because it receives the infrared rays passively and do not emit any infrared ray. The lamp or alarm remains on few…
In this project, a smart socket is designed which can be automatically switched using a relay. The socket is interfaced to a Particle Photon based IoT device which keeps track of energy consumption using ACS 712 Current sensor and help automatically disconnect socket connection with the Mains when the power consumption by a device exceeds a threshold value. The Photon also remains connected to a web server via Wi-Fi hotspot and keeps updating the energy consumption data to the server.
This is a very easy circuit . This can be employed in automobiles as a sequential indicate light. This circuit is constructed with the help of two ICs first one is a CMOS timer IC i.e. 555 timer and another one is the decade counter IC i.e. CD4017. In this circuit astable mode of the 555 timer IC is been used to trigger the counter. Also few other discrete components are used in the circuit.
The circuit presented here operates a relay for Fixed Timer Interval. So the device or machine connected with relay operates for same time. The device once switched ON, automatically switches OFF after Fixed (set) Time Interval when relay switches OFF. The Time Interval can be varied and it is displayed on 7 Segment Display. This kind of circuits can be used in many applications where it is required to operate any device or machine for Fixed Time Interval.
The switch ‘SW’ is connected for testing in such a way that it can close and open the contact with the ground and PIN C of the BOARD_A. The PIN B should be connected with the PIN D so that the INDICATOR module can get positive voltage. Suppose when the power is applied and the…
A person’s inquisitiveness and curiosity can do wonders. It can open a realm of ideas and imaginations never thought before and create something worthwhile. When I was a child I used to read lot of electronic articles and magazines regularly. I’ve seen a lot of interesting circuits and tried as many of them as possible at that time. Whenever a new circuit catches my attention I can’t resist myself trying it out.
Main component of this circuit is IC NE555 timer.IC1 in this circuit works in astable mode. Other components that are used in this circuit are resistor, capacitor, LEDs and transistor.When power supply is on and switch pressed then voltage at pin2 and pin6 of IC1 drops. At the same duration voltage at pin3 of IC1 gets high and LED glows.For driving big quantity of LEDs (say around 50), a PNP transistor T1 (BD140) linked in the output terminal of the circuit.In this circuit we have used only 9 LEDs. We have divided the 9 LEDs in the group of three LEDs which is attached with 82 ohm resistor.
Up to this point, we were developing the basic functions into specific functional blocks according to their requirements. Let’s take a look at what all functional blocks we have, it will give you an idea how far we advanced in the designing processEach of the blocks shown above can perform their own specified functions only. The entire blocks should perform together to give us a collective output. It will happen only when we connect the blocks together in the proper way. Next we are going to discuss how to connect these blocks together so that we have a complete block diagram for the device. From the entire discussion so far you might already have a picture about the way of connecting these blocks together. The IR light from the TV remote triggers the working of the device and who receives the IR light pulses from the TV remote, the IR photodiode.
555 timer IC is highly used IC in the projects as it is low in price as well as provide high performance. You can find large number of projects on the internet made up of using 555 timer. Here is another simple project made with the help of 555 timer which can offer you hour of enjoyment.The project is made with the help of NE555 timer along with support of some other discrete components. The project which is shown here is clearly a triggering circuit and with the support of variable resistor VR1 in the project timing is adjusted.
Explained here is an interesting circuit designing tutorial about impedance measurement of a speaker. In speakers, impedance measurement forms a crucial part as it is always needed to get the perfect every time. From small earphones to the large bass woofers, one cannot expect sound to be too lousy or too sharp even at normal levels. It, hence, becomes the responsibility of the circuit design to get the perfect sound delivered to our ears. Interestingly, impedance variance is quite a common feature in speakers depending on their application. A telephone and a home theater system speaker would have totally different requirements in terms of impedance measurement. This circuit designing tutorial on impedance measurement describes basics with sounds, frequency and impedance. Further, a thorough detail regarding practical impedance measurement has been explained. Explore all the technical details and find out how you can make yourself a master piece of a speaker through this impedance measurement process.
The inductor coil is one of the fundamental electronic componentshowever it is very less used in the electronic circuits as compared to the other components. The reasons are mainly due to its physical size, sensitivity to the presence of electromagnetic field, unavailability of wide range of inductance values etc. The inductors cannot be included in the Integrated Circuit Chips due to its three dimensional geometry and size. Hence most of the circuit designers try to avoid inductor coils from their circuits and prefer ‘Synthetic Inductor Circuits’ which simulates an inductor using other electronic components. This article discusses on the design of a Synthetic Inductor circuit and demonstrates its working on a sample application circuit. The Synthetic Inductor can be easily made using a capacitor, Op-amp, a resistor and a variable resistor using which the inductance value can be varied by a large range. When using SMD components the entire circuit will take less space than the actual inductor.
In an audio play back device, the entire audio signals are separated into different bands and applied to the corresponding type of loudspeaker. The Tweeters are normally fed with frequencies above 5 kHz, Mid-range speakers are fed with frequencies in the range of 300 Hz to 5 kHz, and Sub-Woofers with 300 Hz to 40 Hz and Woofers are fed with frequencies below 40 Hz. Since the musical sound normally falls around the maximum frequency of 5 to 8 KHz, Tweeters are not so common in audio devices. For driving the Mid-range Speakers a high pass filter of cut-in frequency around 300 Hz is enough and for Woofers a Low pass filter with cut-off frequency around 40 Hz will suffice. Bass-beats of the songs appear in the Sub-Woofer range and a Band-pass filter can be used to separate out these frequencies from the entire audio signals. This project discusses the design and implementation of a Multiple Feed Back (MFB) Band pass filter for Sub-Woofer frequencies.
The entire audible voice spectrum stretches from around 20Hz to 20 KHz and there is not loudspeaker design which can reproduce all these frequencies with the same effect. The Woofers are made to produce subsonic sounds (below 20 Hz) and there are musical instruments which can produce frequencies above 18 KHz. To reproduce all these sounds different types of loudspeakers are fed with their own band of frequencies extracted from the music.The filter circuits that are used at the output side of the audio device which filters out different band of frequencies and use them to drive different type of loudspeakers are called Audio Crossover Circuits. Three-way cross over circuits are very common in output side of the audio devices which filters out frequency bands for Tweeters, Mid-range Speakers and Sub-Woofers. This tutorial discusses the design and implementation of Two-way audio cross-over circuit using Active filters for quality filtering.
This article discusses about the design of a simple audio mixer circuit. An op-amp based summing amplifier is used here to mix two sounds. The audio mixing is demonstrated with the help of mixing a high frequency musical sound with a low frequency bass beat, where the musical sound is generated by a musical IC and the bass beat played at a mobile phone and is captured and amplified through a microphone and amplifier circuits. The different sounds in songs like the sound of the guitar, drums, the voice of the singer etc. are recorded as separate tracks using separate microphones. More than 10 numbers of tracks are very common in normal quality songs. How is such a circuit assembled? What are the major precautions and restrictions when using this circuit? Keep on reading this tutorial to find more interesting information about electronics of audio mixing.
The Pulse Position Modulation (PPM) is a modulation technique designed to achieve the goals like simple transmitter and receiver circuitry, noise performance, constant bandwidth and the power efficiency and constant transmitter power. In Pulse Position Modulation the amplitude of the pulse is kept constant as in the case of the FM and PWM to avoid noise interference. Unlike the PWM the pulse width is kept constant to achieve constant transmitter power. The modulation is done by varying the position of the pulse from the mean position according to the variations in the amplitude of the modulating signal. This article discusses the technique of generating a PPM wave corresponding to a modulating sine wave. The Pulse Position Modulation (PPM) can be actually easily generated from a PWM waveform which has been modulated according to the input signal waveform.
The amplifiers are devices which produces an output signal which is several times higher in amplitude than the input signals. The ratio of the amplitude of the output signal from an amplifier circuit to the amplitude of the input signal is called Gain. The amplifier circuits are normally designed for a fixed amount of gain. There are amplifiers with very low gain, like the amplifiers at the loudspeaker side of an audio device and also there are amplifiers with very high gain, like the amplifiers in the radio receivers or amplifiers at the microphone side of an audio device. The Automatic Gain Control (AGC) amplifiers are another category of amplifiers which can vary its gain according to the input signal level. They provide enough amplification for the weak signals and prevent strong signals from getting over amplified.